Perl::Critic::Config takes care of finding and processing user-preferences for Perl::Critic.
The Config object defines which Policy modules will be loaded into the Perl::Critic engine and how they should be configured.
You should never really need to instantiate Perl::Critic::Config directly because the Perl::Critic constructor will do it for you.

Creates a Policy object and loads it into this Config.
If the object cannot be instantiated,
it will throw a fatal exception.
Otherwise,
it returns a reference to this Critic.

-policy is the name of a Perl::Critic::Policy subclass module.
The 'Perl::Critic::Policy' portion of the name can be omitted for brevity.
This argument is required.

-params is an optional reference to a hash of Policy parameters.
The contents of this hash reference will be passed into to the constructor of the Policy module.
See the documentation in the relevant Policy module for a description of the arguments it supports.

Returns a list containing references to all the Policy objects that have been seen.
Note that the state of these objects is not trustworthy.
In particular,
it is likely that some of them are not prepared to examine any documents.

Returns a list of all the Policy modules that are currently installed in the Perl::Critic:Policy namespace.
These will include modules that are distributed with Perl::Critic plus any third-party modules that have been installed.

Most of the settings for Perl::Critic and each of the Policy modules can be controlled by a configuration file.
The default configuration file is called .perlcriticrc.
Perl::Critic::Config will look for this file in the current directory first,
and then in your home directory.
Alternatively,
you can set the PERLCRITIC environment variable to explicitly point to a different file in another location.
If none of these files exist,
and the -profile option is not given to the constructor,
then all Policies will be loaded with their default configuration.

The format of the configuration file is a series of INI-style blocks that contain key-value pairs separated by '='.
Comments should start with '#' and can be placed on a separate line or after the name-value pairs if you desire.

Default settings for Perl::Critic itself can be set before the first named block. For example,
putting any or all of these at the top of your configuration file will set the default value for the corresponding Perl::Critic constructor argument.

Perl::Critic::Policy::Category::PolicyName is the full name of a module that implements the policy. The Policy modules distributed with Perl::Critic have been grouped into categories according to the table of contents in Damian Conway's book Perl Best Practices. For brevity, you can omit the 'Perl::Critic::Policy' part of the module name.

severity is the level of importance you wish to assign to the Policy. All Policy modules are defined with a default severity value ranging from 1 (least severe) to 5 (most severe). However, you may disagree with the default severity and choose to give it a higher or lower severity, based on your own coding philosophy.

The remaining key-value pairs are configuration parameters that will be passed into the constructor of that Policy. The constructors for most Policy modules do not support arguments, and those that do should have reasonable defaults. See the documentation on the appropriate Policy module for more details.

Instead of redefining the severity for a given Policy, you can completely disable a Policy by prepending a '-' to the name of the module in your configuration file. In this manner, the Policy will never be loaded, regardless of the -severity given to the Perl::Critic::Config constructor.

A simple configuration might look like this:

#--------------------------------------------------------------
# I think these are really important, so always load them
[TestingAndDebugging::RequireUseStrict]
severity = 5
[TestingAndDebugging::RequireUseWarnings]
severity = 5
#--------------------------------------------------------------
# I think these are less important, so only load when asked
[Variables::ProhibitPackageVars]
severity = 2
[ControlStructures::ProhibitPostfixControls]
allow = if unless #My custom configuration
severity = 2
#--------------------------------------------------------------
# Give these policies a custom theme. I can activate just
# these policies by saying (-theme => 'larry + curly')
[Modules::RequireFilenameMatchesPackage]
add_themes = larry
[TestingAndDebugging::RequireTestLables]
add_themes = curly moe
#--------------------------------------------------------------
# I do not agree with these at all, so never load them
[-NamingConventions::Capitalization]
[-ValuesAndExpressions::ProhibitMagicNumbers]
#--------------------------------------------------------------
# For all other Policies, I accept the default severity, theme
# and other parameters, so no additional configuration is
# required for them.

For additional configuration examples, see the perlcriticrc file that is included in this t/examples directory of this distribution.

A large number of Policy modules are distributed with Perl::Critic. They are described briefly in the companion document Perl::Critic::PolicySummary and in more detail in the individual modules themselves.

Each Policy is defined with one or more "themes". Themes can be used to create arbitrary groups of Policies. They are intended to provide an alternative mechanism for selecting your preferred set of Policies. For example, you may wish disable a certain subset of Policies when analyzing test programs. Conversely, you may wish to enable only a specific subset of Policies when analyzing modules.

The Policies that ship with Perl::Critic are have been broken into the following themes. This is just our attempt to provide some basic logical groupings. You are free to invent new themes that suit your needs.

THEME DESCRIPTION
--------------------------------------------------------------------------
core All policies that ship with Perl::Critic
pbp Policies that come directly from "Perl Best Practices"
bugs Policies that prevent or reveal bugs
maintenance Policies that affect the long-term health of the code
cosmetic Policies that only have a superficial effect
complexity Policies that specificaly relate to code complexity
security Policies that relate to security issues
tests Policies that are specific to test programs

Say `perlcritic -list` to get a listing of all available policies and the themes that are associated with each one. You can also change the theme for any Policy in your .perlcriticrc file. See the "CONFIGURATION" section for more information about that.

Using the -theme option, you can combine theme names with mathematical and boolean operators to create an arbitrarily complex expression that represents a custom "set" of Policies. The following operators are supported

Operator precedence is the same as that of normal mathematics. You can also use parenthesis to enforce precedence. Here are some examples:

Expression Meaning
----------------------------------------------------------------------------
pbp * bugs All policies that are "pbp" AND "bugs"
pbp and bugs Ditto
bugs + cosmetic All policies that are "bugs" OR "cosmetic"
bugs or cosmetic Ditto
pbp - cosmetic All policies that are "pbp" BUT NOT "cosmetic"
pbp not cosmetic Ditto
-maintenance All policies that are NOT "maintenance"
not maintenance Ditto
(pbp - bugs) * complexity All policies that are "pbp" BUT NOT "bugs",
AND "complexity"
(pbp not bugs) and complexity Ditto

Theme names are case-insensitive. If -theme is set to an empty string, then it is equivalent to the set of all Policies. A theme name that doesn't exist is equivalent to an empty set. Please See http://en.wikipedia.org/wiki/Set for a discussion on set theory.